| 1 | /* |
| 2 | * noVNC: HTML5 VNC client |
| 3 | * Copyright (C) 2020 The noVNC Authors |
| 4 | * Licensed under MPL 2.0 (see LICENSE.txt) |
| 5 | * |
| 6 | * See README.md for usage and integration instructions. |
| 7 | * |
| 8 | */ |
| 9 | |
| 10 | const GH_NOGESTURE = 0; |
| 11 | const GH_ONETAP = 1; |
| 12 | const GH_TWOTAP = 2; |
| 13 | const GH_THREETAP = 4; |
| 14 | const GH_DRAG = 8; |
| 15 | const GH_LONGPRESS = 16; |
| 16 | const GH_TWODRAG = 32; |
| 17 | const GH_PINCH = 64; |
| 18 | |
| 19 | const GH_INITSTATE = 127; |
| 20 | |
| 21 | const GH_MOVE_THRESHOLD = 50; |
| 22 | const GH_ANGLE_THRESHOLD = 90; // Degrees |
| 23 | |
| 24 | // Timeout when waiting for gestures (ms) |
| 25 | const GH_MULTITOUCH_TIMEOUT = 250; |
| 26 | |
| 27 | // Maximum time between press and release for a tap (ms) |
| 28 | const GH_TAP_TIMEOUT = 1000; |
| 29 | |
| 30 | // Timeout when waiting for longpress (ms) |
| 31 | const GH_LONGPRESS_TIMEOUT = 1000; |
| 32 | |
| 33 | // Timeout when waiting to decide between PINCH and TWODRAG (ms) |
| 34 | const GH_TWOTOUCH_TIMEOUT = 50; |
| 35 | |
| 36 | export default class GestureHandler { |
| 37 | constructor() { |
| 38 | this._target = null; |
| 39 | |
| 40 | this._state = GH_INITSTATE; |
| 41 | |
| 42 | this._tracked = []; |
| 43 | this._ignored = []; |
| 44 | |
| 45 | this._waitingRelease = false; |
| 46 | this._releaseStart = 0.0; |
| 47 | |
| 48 | this._longpressTimeoutId = null; |
| 49 | this._twoTouchTimeoutId = null; |
| 50 | |
| 51 | this._boundEventHandler = this._eventHandler.bind(this); |
| 52 | } |
| 53 | |
| 54 | attach(target) { |
| 55 | this.detach(); |
| 56 | |
| 57 | this._target = target; |
| 58 | this._target.addEventListener('touchstart', |
| 59 | this._boundEventHandler); |
| 60 | this._target.addEventListener('touchmove', |
| 61 | this._boundEventHandler); |
| 62 | this._target.addEventListener('touchend', |
| 63 | this._boundEventHandler); |
| 64 | this._target.addEventListener('touchcancel', |
| 65 | this._boundEventHandler); |
| 66 | } |
| 67 | |
| 68 | detach() { |
| 69 | if (!this._target) { |
| 70 | return; |
| 71 | } |
| 72 | |
| 73 | this._stopLongpressTimeout(); |
| 74 | this._stopTwoTouchTimeout(); |
| 75 | |
| 76 | this._target.removeEventListener('touchstart', |
| 77 | this._boundEventHandler); |
| 78 | this._target.removeEventListener('touchmove', |
| 79 | this._boundEventHandler); |
| 80 | this._target.removeEventListener('touchend', |
| 81 | this._boundEventHandler); |
| 82 | this._target.removeEventListener('touchcancel', |
| 83 | this._boundEventHandler); |
| 84 | this._target = null; |
| 85 | } |
| 86 | |
| 87 | _eventHandler(e) { |
| 88 | let fn; |
| 89 | |
| 90 | e.stopPropagation(); |
| 91 | e.preventDefault(); |
| 92 | |
| 93 | switch (e.type) { |
| 94 | case 'touchstart': |
| 95 | fn = this._touchStart; |
| 96 | break; |
| 97 | case 'touchmove': |
| 98 | fn = this._touchMove; |
| 99 | break; |
| 100 | case 'touchend': |
| 101 | case 'touchcancel': |
| 102 | fn = this._touchEnd; |
| 103 | break; |
| 104 | } |
| 105 | |
| 106 | for (let i = 0; i < e.changedTouches.length; i++) { |
| 107 | let touch = e.changedTouches[i]; |
| 108 | fn.call(this, touch.identifier, touch.clientX, touch.clientY); |
| 109 | } |
| 110 | } |
| 111 | |
| 112 | _touchStart(id, x, y) { |
| 113 | // Ignore any new touches if there is already an active gesture, |
| 114 | // or we're in a cleanup state |
| 115 | if (this._hasDetectedGesture() || (this._state === GH_NOGESTURE)) { |
| 116 | this._ignored.push(id); |
| 117 | return; |
| 118 | } |
| 119 | |
| 120 | // Did it take too long between touches that we should no longer |
| 121 | // consider this a single gesture? |
| 122 | if ((this._tracked.length > 0) && |
| 123 | ((Date.now() - this._tracked[0].started) > GH_MULTITOUCH_TIMEOUT)) { |
| 124 | this._state = GH_NOGESTURE; |
| 125 | this._ignored.push(id); |
| 126 | return; |
| 127 | } |
| 128 | |
| 129 | // If we're waiting for fingers to release then we should no longer |
| 130 | // recognize new touches |
| 131 | if (this._waitingRelease) { |
| 132 | this._state = GH_NOGESTURE; |
| 133 | this._ignored.push(id); |
| 134 | return; |
| 135 | } |
| 136 | |
| 137 | this._tracked.push({ |
| 138 | id: id, |
| 139 | started: Date.now(), |
| 140 | active: true, |
| 141 | firstX: x, |
| 142 | firstY: y, |
| 143 | lastX: x, |
| 144 | lastY: y, |
| 145 | angle: 0 |
| 146 | }); |
| 147 | |
| 148 | switch (this._tracked.length) { |
| 149 | case 1: |
| 150 | this._startLongpressTimeout(); |
| 151 | break; |
| 152 | |
| 153 | case 2: |
| 154 | this._state &= ~(GH_ONETAP | GH_DRAG | GH_LONGPRESS); |
| 155 | this._stopLongpressTimeout(); |
| 156 | break; |
| 157 | |
| 158 | case 3: |
| 159 | this._state &= ~(GH_TWOTAP | GH_TWODRAG | GH_PINCH); |
| 160 | break; |
| 161 | |
| 162 | default: |
| 163 | this._state = GH_NOGESTURE; |
| 164 | } |
| 165 | } |
| 166 | |
| 167 | _touchMove(id, x, y) { |
| 168 | let touch = this._tracked.find(t => t.id === id); |
| 169 | |
| 170 | // If this is an update for a touch we're not tracking, ignore it |
| 171 | if (touch === undefined) { |
| 172 | return; |
| 173 | } |
| 174 | |
| 175 | // Update the touches last position with the event coordinates |
| 176 | touch.lastX = x; |
| 177 | touch.lastY = y; |
| 178 | |
| 179 | let deltaX = x - touch.firstX; |
| 180 | let deltaY = y - touch.firstY; |
| 181 | |
| 182 | // Update angle when the touch has moved |
| 183 | if ((touch.firstX !== touch.lastX) || |
| 184 | (touch.firstY !== touch.lastY)) { |
| 185 | touch.angle = Math.atan2(deltaY, deltaX) * 180 / Math.PI; |
| 186 | } |
| 187 | |
| 188 | if (!this._hasDetectedGesture()) { |
| 189 | // Ignore moves smaller than the minimum threshold |
| 190 | if (Math.hypot(deltaX, deltaY) < GH_MOVE_THRESHOLD) { |
| 191 | return; |
| 192 | } |
| 193 | |
| 194 | // Can't be a tap or long press as we've seen movement |
| 195 | this._state &= ~(GH_ONETAP | GH_TWOTAP | GH_THREETAP | GH_LONGPRESS); |
| 196 | this._stopLongpressTimeout(); |
| 197 | |
| 198 | if (this._tracked.length !== 1) { |
| 199 | this._state &= ~(GH_DRAG); |
| 200 | } |
| 201 | if (this._tracked.length !== 2) { |
| 202 | this._state &= ~(GH_TWODRAG | GH_PINCH); |
| 203 | } |
| 204 | |
| 205 | // We need to figure out which of our different two touch gestures |
| 206 | // this might be |
| 207 | if (this._tracked.length === 2) { |
| 208 | |
| 209 | // The other touch is the one where the id doesn't match |
| 210 | let prevTouch = this._tracked.find(t => t.id !== id); |
| 211 | |
| 212 | // How far the previous touch point has moved since start |
| 213 | let prevDeltaMove = Math.hypot(prevTouch.firstX - prevTouch.lastX, |
| 214 | prevTouch.firstY - prevTouch.lastY); |
| 215 | |
| 216 | // We know that the current touch moved far enough, |
| 217 | // but unless both touches moved further than their |
| 218 | // threshold we don't want to disqualify any gestures |
| 219 | if (prevDeltaMove > GH_MOVE_THRESHOLD) { |
| 220 | |
| 221 | // The angle difference between the direction of the touch points |
| 222 | let deltaAngle = Math.abs(touch.angle - prevTouch.angle); |
| 223 | deltaAngle = Math.abs(((deltaAngle + 180) % 360) - 180); |
| 224 | |
| 225 | // PINCH or TWODRAG can be eliminated depending on the angle |
| 226 | if (deltaAngle > GH_ANGLE_THRESHOLD) { |
| 227 | this._state &= ~GH_TWODRAG; |
| 228 | } else { |
| 229 | this._state &= ~GH_PINCH; |
| 230 | } |
| 231 | |
| 232 | if (this._isTwoTouchTimeoutRunning()) { |
| 233 | this._stopTwoTouchTimeout(); |
| 234 | } |
| 235 | } else if (!this._isTwoTouchTimeoutRunning()) { |
| 236 | // We can't determine the gesture right now, let's |
| 237 | // wait and see if more events are on their way |
| 238 | this._startTwoTouchTimeout(); |
| 239 | } |
| 240 | } |
| 241 | |
| 242 | if (!this._hasDetectedGesture()) { |
| 243 | return; |
| 244 | } |
| 245 | |
| 246 | this._pushEvent('gesturestart'); |
| 247 | } |
| 248 | |
| 249 | this._pushEvent('gesturemove'); |
| 250 | } |
| 251 | |
| 252 | _touchEnd(id, x, y) { |
| 253 | // Check if this is an ignored touch |
| 254 | if (this._ignored.indexOf(id) !== -1) { |
| 255 | // Remove this touch from ignored |
| 256 | this._ignored.splice(this._ignored.indexOf(id), 1); |
| 257 | |
| 258 | // And reset the state if there are no more touches |
| 259 | if ((this._ignored.length === 0) && |
| 260 | (this._tracked.length === 0)) { |
| 261 | this._state = GH_INITSTATE; |
| 262 | this._waitingRelease = false; |
| 263 | } |
| 264 | return; |
| 265 | } |
| 266 | |
| 267 | // We got a touchend before the timer triggered, |
| 268 | // this cannot result in a gesture anymore. |
| 269 | if (!this._hasDetectedGesture() && |
| 270 | this._isTwoTouchTimeoutRunning()) { |
| 271 | this._stopTwoTouchTimeout(); |
| 272 | this._state = GH_NOGESTURE; |
| 273 | } |
| 274 | |
| 275 | // Some gestures don't trigger until a touch is released |
| 276 | if (!this._hasDetectedGesture()) { |
| 277 | // Can't be a gesture that relies on movement |
| 278 | this._state &= ~(GH_DRAG | GH_TWODRAG | GH_PINCH); |
| 279 | // Or something that relies on more time |
| 280 | this._state &= ~GH_LONGPRESS; |
| 281 | this._stopLongpressTimeout(); |
| 282 | |
| 283 | if (!this._waitingRelease) { |
| 284 | this._releaseStart = Date.now(); |
| 285 | this._waitingRelease = true; |
| 286 | |
| 287 | // Can't be a tap that requires more touches than we current have |
| 288 | switch (this._tracked.length) { |
| 289 | case 1: |
| 290 | this._state &= ~(GH_TWOTAP | GH_THREETAP); |
| 291 | break; |
| 292 | |
| 293 | case 2: |
| 294 | this._state &= ~(GH_ONETAP | GH_THREETAP); |
| 295 | break; |
| 296 | } |
| 297 | } |
| 298 | } |
| 299 | |
| 300 | // Waiting for all touches to release? (i.e. some tap) |
| 301 | if (this._waitingRelease) { |
| 302 | // Were all touches released at roughly the same time? |
| 303 | if ((Date.now() - this._releaseStart) > GH_MULTITOUCH_TIMEOUT) { |
| 304 | this._state = GH_NOGESTURE; |
| 305 | } |
| 306 | |
| 307 | // Did too long time pass between press and release? |
| 308 | if (this._tracked.some(t => (Date.now() - t.started) > GH_TAP_TIMEOUT)) { |
| 309 | this._state = GH_NOGESTURE; |
| 310 | } |
| 311 | |
| 312 | let touch = this._tracked.find(t => t.id === id); |
| 313 | touch.active = false; |
| 314 | |
| 315 | // Are we still waiting for more releases? |
| 316 | if (this._hasDetectedGesture()) { |
| 317 | this._pushEvent('gesturestart'); |
| 318 | } else { |
| 319 | // Have we reached a dead end? |
| 320 | if (this._state !== GH_NOGESTURE) { |
| 321 | return; |
| 322 | } |
| 323 | } |
| 324 | } |
| 325 | |
| 326 | if (this._hasDetectedGesture()) { |
| 327 | this._pushEvent('gestureend'); |
| 328 | } |
| 329 | |
| 330 | // Ignore any remaining touches until they are ended |
| 331 | for (let i = 0; i < this._tracked.length; i++) { |
| 332 | if (this._tracked[i].active) { |
| 333 | this._ignored.push(this._tracked[i].id); |
| 334 | } |
| 335 | } |
| 336 | this._tracked = []; |
| 337 | |
| 338 | this._state = GH_NOGESTURE; |
| 339 | |
| 340 | // Remove this touch from ignored if it's in there |
| 341 | if (this._ignored.indexOf(id) !== -1) { |
| 342 | this._ignored.splice(this._ignored.indexOf(id), 1); |
| 343 | } |
| 344 | |
| 345 | // We reset the state if ignored is empty |
| 346 | if ((this._ignored.length === 0)) { |
| 347 | this._state = GH_INITSTATE; |
| 348 | this._waitingRelease = false; |
| 349 | } |
| 350 | } |
| 351 | |
| 352 | _hasDetectedGesture() { |
| 353 | if (this._state === GH_NOGESTURE) { |
| 354 | return false; |
| 355 | } |
| 356 | // Check to see if the bitmask value is a power of 2 |
| 357 | // (i.e. only one bit set). If it is, we have a state. |
| 358 | if (this._state & (this._state - 1)) { |
| 359 | return false; |
| 360 | } |
| 361 | |
| 362 | // For taps we also need to have all touches released |
| 363 | // before we've fully detected the gesture |
| 364 | if (this._state & (GH_ONETAP | GH_TWOTAP | GH_THREETAP)) { |
| 365 | if (this._tracked.some(t => t.active)) { |
| 366 | return false; |
| 367 | } |
| 368 | } |
| 369 | |
| 370 | return true; |
| 371 | } |
| 372 | |
| 373 | _startLongpressTimeout() { |
| 374 | this._stopLongpressTimeout(); |
| 375 | this._longpressTimeoutId = setTimeout(() => this._longpressTimeout(), |
| 376 | GH_LONGPRESS_TIMEOUT); |
| 377 | } |
| 378 | |
| 379 | _stopLongpressTimeout() { |
| 380 | clearTimeout(this._longpressTimeoutId); |
| 381 | this._longpressTimeoutId = null; |
| 382 | } |
| 383 | |
| 384 | _longpressTimeout() { |
| 385 | if (this._hasDetectedGesture()) { |
| 386 | throw new Error("A longpress gesture failed, conflict with a different gesture"); |
| 387 | } |
| 388 | |
| 389 | this._state = GH_LONGPRESS; |
| 390 | this._pushEvent('gesturestart'); |
| 391 | } |
| 392 | |
| 393 | _startTwoTouchTimeout() { |
| 394 | this._stopTwoTouchTimeout(); |
| 395 | this._twoTouchTimeoutId = setTimeout(() => this._twoTouchTimeout(), |
| 396 | GH_TWOTOUCH_TIMEOUT); |
| 397 | } |
| 398 | |
| 399 | _stopTwoTouchTimeout() { |
| 400 | clearTimeout(this._twoTouchTimeoutId); |
| 401 | this._twoTouchTimeoutId = null; |
| 402 | } |
| 403 | |
| 404 | _isTwoTouchTimeoutRunning() { |
| 405 | return this._twoTouchTimeoutId !== null; |
| 406 | } |
| 407 | |
| 408 | _twoTouchTimeout() { |
| 409 | if (this._tracked.length === 0) { |
| 410 | throw new Error("A pinch or two drag gesture failed, no tracked touches"); |
| 411 | } |
| 412 | |
| 413 | // How far each touch point has moved since start |
| 414 | let avgM = this._getAverageMovement(); |
| 415 | let avgMoveH = Math.abs(avgM.x); |
| 416 | let avgMoveV = Math.abs(avgM.y); |
| 417 | |
| 418 | // The difference in the distance between where |
| 419 | // the touch points started and where they are now |
| 420 | let avgD = this._getAverageDistance(); |
| 421 | let deltaTouchDistance = Math.abs(Math.hypot(avgD.first.x, avgD.first.y) - |
| 422 | Math.hypot(avgD.last.x, avgD.last.y)); |
| 423 | |
| 424 | if ((avgMoveV < deltaTouchDistance) && |
| 425 | (avgMoveH < deltaTouchDistance)) { |
| 426 | this._state = GH_PINCH; |
| 427 | } else { |
| 428 | this._state = GH_TWODRAG; |
| 429 | } |
| 430 | |
| 431 | this._pushEvent('gesturestart'); |
| 432 | this._pushEvent('gesturemove'); |
| 433 | } |
| 434 | |
| 435 | _pushEvent(type) { |
| 436 | let detail = { type: this._stateToGesture(this._state) }; |
| 437 | |
| 438 | // For most gesture events the current (average) position is the |
| 439 | // most useful |
| 440 | let avg = this._getPosition(); |
| 441 | let pos = avg.last; |
| 442 | |
| 443 | // However we have a slight distance to detect gestures, so for the |
| 444 | // first gesture event we want to use the first positions we saw |
| 445 | if (type === 'gesturestart') { |
| 446 | pos = avg.first; |
| 447 | } |
| 448 | |
| 449 | // For these gestures, we always want the event coordinates |
| 450 | // to be where the gesture began, not the current touch location. |
| 451 | switch (this._state) { |
| 452 | case GH_TWODRAG: |
| 453 | case GH_PINCH: |
| 454 | pos = avg.first; |
| 455 | break; |
| 456 | } |
| 457 | |
| 458 | detail['clientX'] = pos.x; |
| 459 | detail['clientY'] = pos.y; |
| 460 | |
| 461 | // FIXME: other coordinates? |
| 462 | |
| 463 | // Some gestures also have a magnitude |
| 464 | if (this._state === GH_PINCH) { |
| 465 | let distance = this._getAverageDistance(); |
| 466 | if (type === 'gesturestart') { |
| 467 | detail['magnitudeX'] = distance.first.x; |
| 468 | detail['magnitudeY'] = distance.first.y; |
| 469 | } else { |
| 470 | detail['magnitudeX'] = distance.last.x; |
| 471 | detail['magnitudeY'] = distance.last.y; |
| 472 | } |
| 473 | } else if (this._state === GH_TWODRAG) { |
| 474 | if (type === 'gesturestart') { |
| 475 | detail['magnitudeX'] = 0.0; |
| 476 | detail['magnitudeY'] = 0.0; |
| 477 | } else { |
| 478 | let movement = this._getAverageMovement(); |
| 479 | detail['magnitudeX'] = movement.x; |
| 480 | detail['magnitudeY'] = movement.y; |
| 481 | } |
| 482 | } |
| 483 | |
| 484 | let gev = new CustomEvent(type, { detail: detail }); |
| 485 | this._target.dispatchEvent(gev); |
| 486 | } |
| 487 | |
| 488 | _stateToGesture(state) { |
| 489 | switch (state) { |
| 490 | case GH_ONETAP: |
| 491 | return 'onetap'; |
| 492 | case GH_TWOTAP: |
| 493 | return 'twotap'; |
| 494 | case GH_THREETAP: |
| 495 | return 'threetap'; |
| 496 | case GH_DRAG: |
| 497 | return 'drag'; |
| 498 | case GH_LONGPRESS: |
| 499 | return 'longpress'; |
| 500 | case GH_TWODRAG: |
| 501 | return 'twodrag'; |
| 502 | case GH_PINCH: |
| 503 | return 'pinch'; |
| 504 | } |
| 505 | |
| 506 | throw new Error("Unknown gesture state: " + state); |
| 507 | } |
| 508 | |
| 509 | _getPosition() { |
| 510 | if (this._tracked.length === 0) { |
| 511 | throw new Error("Failed to get gesture position, no tracked touches"); |
| 512 | } |
| 513 | |
| 514 | let size = this._tracked.length; |
| 515 | let fx = 0, fy = 0, lx = 0, ly = 0; |
| 516 | |
| 517 | for (let i = 0; i < this._tracked.length; i++) { |
| 518 | fx += this._tracked[i].firstX; |
| 519 | fy += this._tracked[i].firstY; |
| 520 | lx += this._tracked[i].lastX; |
| 521 | ly += this._tracked[i].lastY; |
| 522 | } |
| 523 | |
| 524 | return { first: { x: fx / size, |
| 525 | y: fy / size }, |
| 526 | last: { x: lx / size, |
| 527 | y: ly / size } }; |
| 528 | } |
| 529 | |
| 530 | _getAverageMovement() { |
| 531 | if (this._tracked.length === 0) { |
| 532 | throw new Error("Failed to get gesture movement, no tracked touches"); |
| 533 | } |
| 534 | |
| 535 | let totalH, totalV; |
| 536 | totalH = totalV = 0; |
| 537 | let size = this._tracked.length; |
| 538 | |
| 539 | for (let i = 0; i < this._tracked.length; i++) { |
| 540 | totalH += this._tracked[i].lastX - this._tracked[i].firstX; |
| 541 | totalV += this._tracked[i].lastY - this._tracked[i].firstY; |
| 542 | } |
| 543 | |
| 544 | return { x: totalH / size, |
| 545 | y: totalV / size }; |
| 546 | } |
| 547 | |
| 548 | _getAverageDistance() { |
| 549 | if (this._tracked.length === 0) { |
| 550 | throw new Error("Failed to get gesture distance, no tracked touches"); |
| 551 | } |
| 552 | |
| 553 | // Distance between the first and last tracked touches |
| 554 | |
| 555 | let first = this._tracked[0]; |
| 556 | let last = this._tracked[this._tracked.length - 1]; |
| 557 | |
| 558 | let fdx = Math.abs(last.firstX - first.firstX); |
| 559 | let fdy = Math.abs(last.firstY - first.firstY); |
| 560 | |
| 561 | let ldx = Math.abs(last.lastX - first.lastX); |
| 562 | let ldy = Math.abs(last.lastY - first.lastY); |
| 563 | |
| 564 | return { first: { x: fdx, y: fdy }, |
| 565 | last: { x: ldx, y: ldy } }; |
| 566 | } |
| 567 | } |